diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index 4f407eabc05..644bd2b8d1b 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -210,7 +210,7 @@ BODY is evaluate only if `comp-debug' is non nil."
     (cond (noninteractive
 	   (message " %s" string))
 	  (t
-	   (insert (format "%s\n" string))))))
+	   (insert string "\n")))))
 
 (defun comp-prettyprint (data)
   "Nicely print DATA in the current buffer."